VEDANTA LTD. (CAIRN OIL & GAS)

Transcription

1 Pre-Feasibility Report For Onshore Oil and Gas Exploration and Appraisal in Block CB- ONHP-2017/6 in Gandhinagar, Ahmedabad and Mahesana Districts of Gujarat VEDANTA LTD. (CAIRN OIL & GAS) March, 2019

2 Table of Contents 1. Executive Summary Project Details Pollution control measures Pollution Control measures during Seismic Operations Pollution Control measures during Drilling Operations Project schedule and cost estimate Employment Generation Rehabilitations and Resettlements Introduction of the project Project Description Type of project Location with co-ordinates Project description with process details Raw materials required and source Water and power requirement Quantity of waste to be generated and its disposal Schematic of Feasibility Drawing Site Analysis Connectivity Topography (along with map) Existing land use pattern and relative location of protected areas Existing infrastructure/ industries Soil classification Climate data from secondary sources Wind Storms and cyclones Rainfall Temperature and humidity Planning Brief Planning concept Population projection Land use planning (break up along with green belt, etc) Assessment of Infrastructure demand

3 7. Rehabilitation and resettlement (R&R) Plan Proposed Infrastructure Project schedule and cost estimate List of Tables Table-1: Co-ordinates of Block CB-ONHP-2017/6 boundary (as per RSC)...9 Table-2: Specific details of the proposed well...13 Table 3: Tentative well co-ordinates to be drilled in block CB-ON-HP-2017/ Table 4: Water requirement Table 5: Expected Waste generation from well drilling...26 Table 6: Climatological Summary at IMD Ahmedabad ( ) List of Figures Figure-1: Location map of block CB-ONHP-2017/6 with state and district boundary... 9 Figure-2: A typical illustration of online 3D seismic survey Figure-3: Flow Chart Showing Various Phases of Drilling Activities.12 Figure-4: Model of Drilling Process Figure-5: Google map with Tentative Location of proposed wells on satellite map..14 Figure-6. Toposheet map with Tentative Location of proposed wells on satellite map...15 Figure-7: Typical configuration of a Drilling Rig Figure-8: Flow Chart for Drilling Mud & Solid Discharge Figure9: Schematic for a typical Well Pad

4 1. Executive Summary Vedanta (erstwhile Cairn India Limited merged with Vedanta Limited w.e.f. April 11, 2017, pursuant to NCLT order dated March 23, 2017) is a globally diversified natural resources company with interest in Zinc, Iron Ore, Aluminium, Copper, Power and Oil & Gas. Vedanta Ltd. (Cairn Oil & Gas) is the operator of the Onshore CB-ONHP-2017/6 block. The block covers an area of 19 Sq.Km in Gandhinagar, Ahmedabad and Mahesana districts of Gujarat. Vedanta Ltd. has been granted with an exploration and production license by Government of India under the Revenue Sharing Contract (RSC) on 1 st October Project Details Proposed facilities Vedanta Limited (Cairn Oil & Gas) proposes to carryout seismic survey, exploratory including appraisal well drilling and setting up of Early Production Units (EPUs)/Quick Production Units (QPUs) and Early production in the block CB-ONHP-2017/ Justification of the project The demand for petroleum has recorded a considerable increase over the last few years. There is a considerable increase in consumption of petroleum products due to the development activities in the country in the last few years. During the year , the consumption of petroleum products in India was MMT with a growth of 5.37% as compared to consumption of MMT during The consumption of petroleum products during April-November, 2017 was at MMT i.e. an increase of 3.40% over MMT in April-November, The crude oil production for the year is at Million Metric Tonnes (MMT) as against production of MMT in , showing a decrease of about 2.53%. Whereas Natural Gas production during the year is at Billion Cubic Meters (BCM) which is 1.09% lower than production of BCM in Import of crude oil during was MMT valued at crore as against import of MMT valued at crore in which marked an increase of 5.46% in quantity terms and 12.86% in value terms as compared to the import of crude oil during Import of Crude Oil during April-November, 2017 was MMT valued at 3,42,673 crore which marked an increase of 9.31% in quantity terms and 15.32% in value terms as against the imports of MMT valued at 2,97,161 crore for the same period of last year. Therefore, India is largely dependent on import of petroleum goods to meet its requirements. Facing an environment of increasing consumption, static reserves, increasing imports and increasing costs of crude as well as decreasing value of the Indian Rupee vis-à-vis the US Dollar, it follows that any accretion of hydrocarbon reserves in the country, is welcome. Vedanta s proposed exploratory drilling, development and production project could possibly result in the discovery of hydrocarbon and in that case, would help in reducing India s dependence on imports. 1.2 Site Analysis Climate The study area experiences a humid and warm sub-tropical climate throughout the year except for a cold winter in December till February. Hourly micro-meteorological data collected during the premonsoon reveals that the pre-dominant wind direction is from SouthEast with an average speed of 0.80 m/s. 4

5 1.3 Water and power requirements Water Requirement A. Water Requirement during Seismic Survey The water requirement is m 3 /day for domestic needs of the temporary campsite and will be sourced locally through approved authorities. B. Water requirement during Exploratory and Appraisal well drilling The most significant requirement of water for drilling activities is for mud preparation. The water requirement for WBM preparation will be m3/well. The water requirement for SBM preparation will be m3/well. The other requirement approx m3/well/day would be for drilling activities like engine cooling, floor / equipment / string washing, fire-fighting storage / make-up. For domestic consumption, approx m3/day water will be required during drilling period. The water requirement will be sourced locally through approved authorities Power requirement A. Power requirement during seismic Survey Each camp site shall have access to 2x 350KVA (1 standby). The required power supply will be provided either from diesel generators or state grid. B. Power requirement during Exploratory and Development well drilling The power requirement of drill rig will be met by three (03) DG sets (including one as standby) (3*1000 KVA), 2*350 KVA for drilling camp site and 2* 100 KVA for the radio room respectively. 1.4 Pollution control measures Pollution Control measures during Seismic Operations A. Air Emissions and Control Measure Emissions to air include transient airborne dust raised by construction activities (e.g. preparation of seismic cut lines and moving vehicles and equipment) and emissions from vehicles and machinery. These emissions are transient and insignificant nature. B. Noise Emissions and Control Measure Noise emissions that could be released during the seismic operations will include those generated by blasting of charges in shot holes, field machinery (Bulldozer and support vehicles) and generators and work yard at the camp site. Adequate noise control measures will be taken to minimize the noise level. C. Wastes treatment and disposal The non-hazardous wastes like domestic wastes and effluents, plastics, and paper and disposal options include, compaction and removal from site and burying (especially for biodegradable material), or a combination of these activities Pollution Control measures during Drilling Operations A. Air Emissions and Control Measure The emissions to the atmosphere from the drilling operations shall be from the diesel engines, and power generator and temporary from flaring activity (during testing). 5

6 B. Noise Emissions and Control Measure The source of noise generation during this phase of operations would be the operation of rig and diesel generator sets. Besides, certain pumps are expected to be in operation during this phase, for mud circulation. The noise generation work however is transient and limited to the drilling period only. Appropriate control measures will be taken to minimize exposure of noise to drilling personnel. C. Waste treatment and disposal tons/well for drill cuttings associated with WBM and tons/well for drill cuttings associated with SBM and tons/well WBM spent/residual drilling mud will be generated at site during drilling operations. This will be stored in well-designed HDPE line pit. Used /waste Oil During the drilling approx. 1-2 tons of used oil, sludge containing oil and other drilling wastes will be tons/well will be generated per well. This oil will be sent to authorized recyclers. Domestic waste of kg/day per well will be generated at site, which will be segregated at source (Organic/ Inorganic) and disposed accordingly. All kinds of waste will be disposed in accordance with the requirement of CPCB/SPCB. D. Waste water Treatment The drilling waste water will be treated suitably. 1.5 Project schedule and cost estimate Vedanta Ltd (Cairn Oil and gas) has planned to carryout proposed project activities in the CB-ONHP- 2017/6 Block in next years. The estimated cost of the project is given below: 1) Physical Surveys Cost estimated to be approximately INR 2 Crore. 2) Average Cost per well for exploratory & appraisal well drilling is estimated to be INR 7 Crore. 3) Average cost of a QPF (Quick Processing Facility) is estimated to be INR Crore. 1.6 Employment Generation The seismic surveys are expected to take about 6 to 8 months and will require a crew of approximately 400 to 500 persons. Most of the workforce will be from local nearby areas. During the site preparation for drilling, approximately workmen will be employed per drill site. During the drilling phase, about 50 workmen per shift will be working on site. This will include technical experts, who will be responsible for various drilling related activities and some technical manpower engaged are either from Vedanta Limited or contractor s crew as applicable. It is anticipated that, at any given time, there will be about personnel working on site including technical staff, drilling crew, security staff etc. 1.7 Rehabilitations and Resettlements For exploration, appraisal and production activities, the project does not envisage any R & R of the project, since the land requirement would be very less and on temporary short term lease and away from the settlements. If the identified lands are of private landowners then land lease mode will be applied and in case of govt. land, land allotment from Govt. to be applied. Initially 6

7 temporary short term lease will be taken for 3-5 years for exploration purpose and in case of commercially viable discovery of hydrocarbon resources; the land lease would be converted into long term lease up to life of the project. For sites selected having settlements if any, Resettlement & rehabilitation (R&R) plan will be developed and implemented as per the applicable State/ Central Govt. policy. Compensation to affected landowners for any loss of land, Cairn will ensure the livelihood of local community, if any affected by the proposed land take, are identified and compensated through adequate compensation and other livelihood restoration activities directly or indirectly through CSR activities. 2. Introduction of the project 2.1 Identification of the project Vedanta Ltd (Cairn Oil & Gas) has been awarded the CB-ONHP-2017/6 hydrocarbon block under the OALP (Open Acreage Licensing Policy) by MoP&NG, Govt. of India. RSC (Revenue Sharing Contract) has been signed between Vedanta Ltd and MoP&NG on 1 st October, 2018 for the exploration and exploitation of hydrocarbons. Vedanta Ltd (Cairn Oil & Gas) proposes to carry out exploration (including seismic surveys, exploratory and appraisal well drilling), and early production of oil and gas in the block. In case of a discovery (ies), the exploratory and appraisal well(s) will be tested for extended duration by flowing hydrocarbons to ascertain the reservoir parameters and assess the quality and commercial viability. Moreover, in case of commercially viable discovery (s) of hydrocarbons in the block and having established the size of the hydrocarbon field (s), field will be immediately brought into early production of crude oil and associated gas using some of the successful exploratory/appraisal wells by setting up of temporary and mobile Early Production Units (EPUs)/QPU (Quick Production Unit) for the processing of produced well fluids. 2.2 Brief description of nature of the project The proposed project is green field in nature. The project is an oil and gas exploration and early production project. 2.3 Need for the project and its importance to country and region India is largely dependent on import of petroleum goods to meet its requirements. Facing an environment of increasing consumption, static reserves, increasing imports and increasing costs of crude as well as decreasing value of the Indian Rupee vis-à-vis the US Dollar, it follows that any accretion of hydrocarbon reserves in the country, is welcome. Vedanta s proposed exploratory drilling project could possibly result in the discovery of hydrocarbon and subsequent development and production would help in reducing India s dependence on imports. Consequently, the need for the project is evident. The proposed project would also contribute to the state Governments in terms of royalty through the mining lease. Additionally the proposed project would generate direct and indirect employment in the region. 2.4 Demand-supply Gap As on , In-place hydrocarbon volume of million tonnes of oil and oil equivalent gas could be established through exploration by ONGC, OIL and Private/JV companies. So, about 75% of 7

8 resources are under yet to find category. Out of MMT of oil and oil equivalent gas of Inplace volumes, the ultimate reserves which can be produced are about 4017 MMT of oil and oil equivalent gas since inception. The balance recoverable reserves are of the order of 1787 MMT of oil and oil equivalent gas Production and Consumption The crude oil production for the year is at Million Metric Tonnes (MMT) as against production of MMT in , showing a decrease of about 2.53%. Whereas Natural Gas production during the year is at Billion Cubic Meters (BCM) which is 1.09% lower than production of BCM in The demand for petroleum has recorded a considerable increase over the last few years due to the development activities in the country in the last few years. During the year , the consumption of petroleum products in India was MMT with a growth of 5.37% as compared to consumption of MMT during The consumption of petroleum products during April-November, 2017 was at MMT i.e. an increase of 3.40% over MMT in April-November, 2016 Therefore, India is largely dependent on import of petroleum goods to meet its requirements. Vedanta s proposed exploratory drilling project could possibly result in the discovery of hydrocarbon and in that case, would help in reducing India s dependence on imports Imports Import of crude oil during was MMT valued at crore as against import of MMT valued at crore in which marked an increase of 5.46% in quantity terms and 12.86% in value terms as compared to the import of crude oil during Import of Crude Oil during April-November, 2017 was MMT valued at 3,42,673 crore which marked an increase of 9.31% in quantity terms and 15.32% in value terms as against the imports of MMT valued at 2,97,161 crore for the same period of last year. 2.5 Import versus indigenous production and export India imports more than 80% of the petroleum products of its daily requirement. 2.6 Domestic Markets The produced Oil & Gas, in case of commercially viable discoveries of hydrocarbon, will be utilized for domestic purpose to supply the increasing demand in domestic market. 2.7 Employment generation The seismic surveys and drilling operations are expected to take about 6 to 8months to complete and will require a crew of approximately 400 to 500 persons. And most of the workforce will be from local area. During the site preparation for drilling, approximately workmen will be employed per drill site. During the drilling phase, about 50 workmen per shift will be working on site. This will include technical experts, who will be responsible for various drilling related activities and some technical manpower engaged are either from Vedanta Limited or contractor s crew as applicable. It is anticipated that, at any given time, there will be about personnel working on site including 8

9 technical staff, drilling crew, security staff etc. In case of commercial discovery of oil and gas additional manpower will be employed for building of production facilities and laying of pipelines. 3 Project Description 3.1 Type of project The proposed project is a green field project. There is no interlinked and inter-dependent project. 3.2 Location with co-ordinates The block CB-ONHP-2017/6 is located in Gandhinagar, Ahmedabad and Mahesana districts of Gujarat. It encloses an area of 19 Sq. Km. and is bounded by the points having following coordinates Table-1. A map of the contract area is shown in Figure 1. Figure-1: Location map of block CB-ONHP-2017/6 with state and district boundary Table-1: Co-ordinates of Block CB-ONHP-2017/6 boundary (as per RSC) Points Longitude Latitude ' 23 7' ' 23 6' 9

10 ' 23 6' ' 23 2' ' 23 2' ' 23 5' ' 23 5' ' 23 7' The block area covers total of 19 Sq. Km falls under Gandhinagar, Ahmedabad and Mahesana districts of Gujarat. 3.3 Details of alternate site considered and the basis of selecting the proposed site The block is allocated by the Government of India under the Revenue Sharing Contract (RSC). Vedanta Ltd. - Cairn Oil & Gas is the Operator for this block. Drilling locations are proposed based on geo-scientific information and alternate sites cannot be considered for the proposed project facilities due to the following reasons: The location is within the existing RSC boundary of the field/block. The locations of wells are selected considering the drilling configuration (reach to reservoirs). 3.4 Size/ magnitude of operation The proposed onshore oil and gas Exploration, Appraisal and Early production project is expected to carry out 1. Seismic data acquisition 2. Drilling of 20 exploratory (including appraisal wells) and testing 3. Setting up of Early Production Units (EPUs)/Quick Production Units (QPUs) for produced well fluid processing and early production of up to 8000 BOPD crude oil and up to 1.2 MMSCFD of associated natural gas 4. The exploratory and appraisal wells will be drilled to explore the reservoirs up to depth of approx m. 3.5 Project description with process details D & 3D Seismic survey: Seismic surveys are a primary tool utilized during the exploration of hydrocarbons over land and water. A seismic survey is conducted by creating an energy wave commonly referred to as a seismic wave on the surface of the ground/ over water along a predetermined line, using an energy source. This wave travels into and through the earth strata, where it is reflected and refracted by various subsurface formations, and returns to the surface where receivers called geophones are used to detect the waves and convey them to a recorder for analysis. Seismic waves can be induced by the following methods: small explosive charges, primarily dynamite, set off in shallow holes known as shot holes ; or by large Vibroseis trucks equipped with heavy plates that vibrate on the ground or air guns for water based surveys. By analyzing the time it takes for the seismic waves to reflect off subsurface formations and return to the surface formations can be mapped and potential oil or gasdeposits identified. 3D surveys are acquired by laying out energy source points (vibroseis or dynamite charges) and receiver points (geophones) in a grid over the area to be surveyed. The receiver points - to record the reflected vibrations from the source points - are laid down in parallel lines (receiver lines), and the source points are laid out in parallel lines that are approximately 10

11 perpendicular to the receiver lines. The spacing of the source and receiver points is determined by the design and objectives of the survey. Figure 2 shows the typical layout of online 3D seismic survey. Figure-2: A typical illustration of online 3D seismic survey To estimate the thickness and seismic velocity of the weathered zone as well as the sub-weathering velocity, Seismic 'upholes' (drill holes (20 50m in depth)) placed at regular intervals (1 2km) along exploration seismic lines. These data are then used in computing time corrections to a nominal seismic datum, which is a fundamental step in computer processing of seismic field data. The upholes will be drilled by a small truck-mounted rig usually using compressed air to lift soil cuttings, adding water occasionally to lift gravelly material. Apart from soil, ground sandstone and groundwater, no chemicals will be added to the drilling fluid only small quantities of bentonite clay if required during backfilling to seal off any encountered groundwater. Once recordings have been made, the majority of the cuttings will be returned to the hole. The cuttings present no risk to the environment in toxicity terms. Excess cuttings at each Uphole, if any, are placed on top of the Uphole and will integrate into the soil over time. 3D seismic surveys are generally conducted in a similar way to 2D seismic surveys but with the variation of setting up six or eight geophone cables side by side at the same time at a distance in most cases of about 100 to 400 metres apart. Several shots from calculated positions along and between the receiver lines are taken, before the cables are moved up and the process repeated. 3D seismic surveys must be conducted over a large area in order to provide sufficient data for accurate interpretation of the subsurface geology. The data collected can later be combined into a single data set for processing and analysis, provided there is sufficient overlap of the areas covered by the surveys. Computer analyses of the recorded seismic waves provide a profile of the underlying rock strata and offer the basis for identifying potential hydrocarbon traps Drilling of Exploration and Appraisal well: Vedanta Ltd. (Cairn Oil & Gas) proposed to drill 69 exploration & appraisal wells within the present block boundary of CB-ONHP-2017/6. 11

12 The basic objective of the exploratory drilling will be as follows:- To determine the presence of potential hydrocarbon To appraise discovered oil & gas The lifecycle of drilling activities involve well site selection, site and access road preparation and its maintenance, construction of drilling well, drilling activities, well testing and decommissioning and closure of wells, if not proved economically viable for production of oil and gas. The following are the commonly used terms in an oil and gas project. If a discovery is made it is likely to need to be appraised. This is an intermediate step between exploration and development which is necessary to confirm the reserve size and field deliverability to an acceptable degree of accuracy. This may be in order to determine whether the discovery is commercial, or to establish the parameters necessary to define the optimal development scheme for the field. Appraisal may consist of additional seismic, further drilling or extended testing of an existing well. Any or all of these types of operations may be deemed desirable or necessary. To Support the drilling operation, the following systems and services will be included at the rig package: Portable Living quarters To house Essential personnel on site on a 24 hr basis.these units are provided with Bath/Washroom. Crane age- Crane for loading/off- loading equipment and supplies. Emergency Systems- It includes fire detection and protection equipment. Environmental Protection Blow Out prevention (BOP) system, Wastewater treatment unit, cutting handling equipment. Additionally, there will be other ancillary facilities like Drilling mud system, ETP, Cuttings disposal, Drill Cementing equipment etc. and utilities to supply Power (DG sets), water, fuel (HSD) to the drilling process and will be set up as a part of the project. The following flow chart of Fig 3 and Fig 4 shows the various phases of the drilling activities and model of drilling process respectively: Figure-3: Flow Chart Showing Various Phases of Drilling Activities 12

13 Figure-4: Model of Drilling Process Location & Description of Drilling Wells The exact locations for the drilling exploratory and appraisal of wells will be fixed once the detailed interpretation of the acquired seismic survey is over. However, the wells will be strictly confined within the acquired block itself. Since the exact drilling locations are yet to be determined, the details of the block location are provided herewith. The acquired exploratory block CB-ONHP-2017/6 is situated in Gandhinagar, Ahmedabad and Mahesana districts of Gujarat. The tentative drilling locations are presented in satellite image (Figure-5) and Survey of India toposheet (Figure-6). Specific details are given in Table-2 and the tentative co-ordinate of the wells is given in the Table 3. The proposed well depths may vary from 1750m to 5000m due to the subsurface structural configuration and the depth of occurrence of the primary reservoirs. Typically estimated drilling duration is days/ well. In general, exploratory and appraisal well testing duration is about 30 days/well. However, depending on the need, based on nature of the reservoirs, the exploratory and appraisal wells will be tested for longer (extended) durations to ascertain the reservoir parameters. Water Base Mud (WBM) will be used as drilling fluid for initial, shallower sections where massive shale not encountered. The deeper and difficult to drill geological formations will be drilled using Synthetic Base Mud (SBM) as drilling fluid. Table-2: Specific details of the proposed wells Well Details Detailed Information Well Locations Depth of Wells Tentative co-ordinates in Table m 13

14 Total Estimation of drilling period Total Estimated Testing Period Proposed Drilling Fluid days/ well days/ well Water Based Mud in shallower section and SBM (Synthetic based mud) in the deeper section. Figure-5. Google map with Tentative Location of proposed wells on satellite map 14

15 Figure-6. Toposheet map with Tentative Location of proposed wells on satellite map Table 3: Tentative well co-ordinates to be drilled in block CB-ON-HP-2017/2 Well id Longitude Latitude ' " E 23 2' " N ' " E 23 2' " N ' " E 23 2' " N 15

16 Well id Longitude Latitude ' " E 23 2' " N ' " E 23 3' " N ' " E 23 3' " N ' " E 23 3' " N ' " E 23 3' " N ' " E 23 4' " N ' " E 23 4' " N ' " E 23 5' 1.382" N ' " E 23 5' 1.966" N ' " E 23 5' " N ' " E 23 5' " N ' " E 23 5' " N ' " E 23 5' " N ' " E 23 6' " N ' " E 23 6' " N ' " E 23 6' 5.531" N ' " E 23 6' 6.119" N Note: - Actual geo-graphical surface coordinates of exploratory and appraisal well locations would be within 2000m radius of the proposed coordinates. Site Selection The exploration history of the area exhibits the potential presence of the oil and gas in the region. The seismic data interpretation of the seismic survey would decide the exact locations of the drilling well.the proposed exploratory well site will be identified based on the study and interpretation of the stratigraphy and seismic data. Within the identified location the actual well drilling site will be selected based on the following factors: Located at least 200 m away from the nearest habitat / sensitive receptors Located at a safe distance (at least the boom / mast length away) from public road Safe distances from any radio transmitters so that the use of explosives and detonators may proceed without the danger of external activation Ensure natural drainage channels are avoided or drainage channels rerouted to ensure unhindered flow of rain / flood water. Where necessary adequate erosion control measures will be provided Land acquisition An area of about 300m X 300m would be taken on temporary lease basis for the construction of well pad / drill site etc for exploratory and appraisal wells. For the preparation of suitable access roads connecting to well pads, laying of infield interconnecting pipelines, OHL and laying pipelines for utilities in future, a width of 30m RoU (approx.) will be required. Wherever needed, infield interconnecting pipeline will be laid. 16

17 Site Preparation Site preparation will involve all activities required to facilitate the operation of the drilling rig and associated equipment s and machineries. At the initial stage, the drilling site will be elevated to about 2.0 m from the existing ground level with minimal clearance of existing ground vegetation. The loose top soil will be removed by using mechanical means like bulldozer and saved at a nearby place for later use during site restoration. Leveling and compaction will be done with the help of graders and mechanical rollers. The land filling materials and rubbles will be required for the purpose of site preparation in sufficient amount. All such materials will be procured by Vedanta through contractors and it will be ensured that they source the materials from government approved borrows and quarries. A backhoe will be used for all excavation and cutting activities (for construction of pits) on site. Subsequently, the proposed well site & campsite will be duly fenced using chain link and barbed wires. Mobilization of Rig The proposed drilling shall be carried out by using a standard land rig or a Mobile Land Rig with standard water based drilling fluid treatment system. This rig will be suitable for deep drilling up to the desired depth of 3500 meters as planned for the project. The typical configuration of a Drilling Rig is shown in the Figure 7. Additionally, there will be other ancillary facilities like Drilling mud system, ETP, Cuttings disposal, Drill Cementing equipment etc. and utilities to supply power (DG sets), water, fuel (HSD) to the drilling process and will be set up as a part of the Project. Details of the drilling rig Type of Rig Drilling mud composition Power generator type & nos. Details of solids handling systems on rig Electrical Rig Water based Drilling Fluid AC SCR Type. (03 Nos.) Shale Shakers GPM Capacity Desander 1200 GPM Capacity Desilter 1200 GPM Capacity 17

18 Figure-7: Typical configuration of a Drilling Rig Drilling Activities Initial Well Construction Wells will be drilled in sections, with the diameter of each section decreasing with increasing depth. Before commencing the actual drilling, large diameter pipe (Conductor) will be lowered into a hole and cemented/grouted. Conductor pipes provide a conduit for the return fluid during drilling next section and also prevent whole unconsolidated material falling into hole and potential washout problems. Typical depths of such pipes are 6m. The lengths and diameters of each section of the well will be determined prior to the starting of the drilling activities and are dependent on the geological conditions through which the well is to be drilled. Once each section of the well is completed, the drill string is lifted and protective steel pipe or casing lowered into the well and cemented into place. The casing helps to maintain the stability of the hole and reduce fluid losses from the well bore into surrounding rock formations. The Drilling Process A rig will be installed at the potential site of drilling after thorough inspection for its working capability and quality standards. Well spudding shall be the start of drilling activity. Top-hole section will be drilled to a desired depth based on well design. After drilling top-hole section, it will be cased with a pipe called Casing. Casing provides support to hole wall and secures hole section. Other than that, it isolates problematic hole sections such as loss zones, shale sections, over pressurized formations etc. After running casing, space between hole wall and Casing (annulus) will be cemented. This process of drilling and casing the hole section continues until the final well depth 18

19 (target) is achieved. Drilling process is associated with various hazards such as well active situation (kicks), blowouts, H2S situation etc Mud System and Cuttings During drilling operations, the drilling fluid (or mud) is pumped through the drill string down to the drilling bit and returns at the drill pipe casing annulus up to surface back into the circulation system after separation of drill cuttings /solids through solids control equipment. The primary function of drilling fluid is to ensure that the rock cuttings generated by the drill bit are continuously removed from the wellbore. The mud must be designed such that it can carry the cuttings to surface while circulating, suspend the cuttings while not circulating and drop the cuttings out of suspension at the surface. The drilled solids are removed at the surface by mechanical devices such as shale shakers, de-sanders and de-silters. The hydrostatic pressure exerted by the mud column prevents influx of formation fluids into the wellbore. The instability caused by the pressure differential between the borehole and the pore pressure can be overcome by increasing the mud weight. Hydration of the clays can be overcome by using non aqueous based muds, or partially addressed by treating the mud with chemicals which will reduce the ability of the water in the mud to hydrate the clays in the formation. Water based mud will be used for initial, shallower sections where massive shales are not encountered. The deeper and difficult to drill formations will be drilled using synthetic base mud (SBM). Synthetic base mud unlike oil based mud (OBM) is biodegradable but can be re-used. At the end of drilling a well almost the entire amount of the SBM is collected for re-use in next drilling operation. SBM systems promote good hole cleaning and cuttings suspension properties. They also suppress gas hydrate formation and exhibit improved conditions for well bore stability compared to most WBM. WBM typically consists of water, bentonite, polymers and barite. Other chemical additives viz. glycols and salts may be used in conjunction to mitigate potential problems related to hydrate formation. The mud to be used will be continuously tested for its density, viscosity, yield point, water loss, ph value etc. The mud will be prepared onsite (drill location) using centrifugal pumps, hoppers and treatment tanks. During drilling activity, cuttings will be generated due to crushing action of the drill bit. These cuttings will be removed by pumping drilling fluid into the well via triplex mud pumps. The mud used during such operation will flush out formation cuttings from the well hole. Cuttings will be then separated from drilling mud using solids-control equipment. This will comprise a stepped system of processes consisting of linear motion vibrating screens called shale shakers, hydro-cyclones (including de-sanders and de-silters), and centrifuges to mechanically separate cuttings from the mud. Figure 8 shows the schematic layout of drilling mud & solids discharge involved as a part of the drilling system for exploratory wells. 19

20 Figure-8: Flow Chart for Drilling Mud & Solid Discharge Cementing Cementing is a necessary aspect of exploratory and appraisal drilling oil and gas wells. Cement is used to fulfill the following works: Secure/support casing strings Isolate zones for production purposes Cementing generally utilizes Portland cement (API Class G Oil Well Cement) with various additives in small quantities as accelerators/retarders, density adjusters, dispersants, fluid loss additives, anti gas migration additives etc. Well Evaluation During the drilling operations for different zones, logging operations will be undertaken to get information on the potential type and quantities of hydrocarbons present in the target formations. Technicians employed by a specialist logging Service Company do well logging by different well logging techniques including electric, sonic and radioactive techniques. Logging instruments (sensors) are attached to the bottom of a wire line and lowered to the bottom of the well and they are then slowly brought back. The devices read different data as they pass each formation and record it on graphs, which will be interpreted by the geologist, geophysicist and drilling engineer. No emissions to the environment or any environmental harm is associated with wire line logging operations. The radioactive source required for well logging operations will be kept in specially designed container. In this drilling procedure, once the drilling is over, the well evaluation will be done by using electric wire line logs to assess the potential of the reservoir. This typically involves sampling the reservoir formation and pressure points during logging operations and reduces the requirement to flow hydrocarbons to the surface, significantly reducing the atmospheric emissions 20

21 associated with the testing operation. Normally, in the event that hydrocarbons are encountered in sufficient quantities, as determined by electric wire line logs, a temporary drill stem test string may be run and the well fluids flowed to surface and processed using a surface well testing package, involving the oil being stored and trucked off the site and associated gas being flared to atmosphere. Hydraulic Fracturing for Tight Rock Reservoirs of Hydrocarbons Hydraulic fracturing is used in tight rock reservoirs with low permeability, such as shale (i.e., the conductivity or ability of hydrocarbons to flow in the formation is low because of the small pore size in the rock). The goal of hydraulic fracturing in tight reservoir (shale) formations is to enable a well to produce the resource or to increase the rate at which a well is able to produce the resource. Hydraulic fracturing may be conducted in wells with low permeability formation and low pressure. Wells requiring hydraulic fracturing and numbers of stages of hydraulic fracturing per well will depend on seismic data acquired & interpreted and data acquired during the drilling phase of the project. Hydraulic fracturing is a common technique used to stimulate the production of oil and natural gas by creating fractures or cracks that extend from the well hole into the rock formations. This is accomplished by injecting fluid, which is usually a mixture of water and high viscosity fluid additives, under extremely high pressure. The pressure of the water will then exceed the strength of the rock, causing fractures to enlarge. After the fractures take place, a propping agent known as proppant (which is usually sand) is injected into the fractures to keep them from closing. This allows the hydrocarbon to move more efficiently from the rock to the well. A single well may require up to 15,000 m 3 of water which may vary depending on the fracking requirements. For the hydraulic fracturing in a well, proppant mass of 150, ,000 lbs per stage and fluid volume of 2500 bbls 4000 bbls per stage will be required. Fracturing effluent generated will be discharged in the HDPE lined pits at the drilling well sites. Additional land will be procured wherever required. For effective recycling and reuse of the fracfluid, effluent treatment plant (ETP) will be installed, thus raw water required for fracturing will be minimized. Well Testing & Flaring During the exploration and appraisal drilling, where a hydrocarbon formation is found, initial well tests (generally about one month of duration) will be carried out to establish flow rates, formation pressure and other parameters. However, depending on the need, based on nature of the reservoirs, the exploratory and appraisal wells will be tested for longer/extended durations to ascertain the reservoir parameters. During the well testing, crude oil, natural gas and produced water could be generated and will be treated/ disposed appropriately. Hydrocarbons will be flared. Efficient test flare burner will be used to minimize incomplete combustion. As an alternative option, if feasible, crude oil/ slop oil will be transferred to nearby refinery (terminals/depots) for processing or will be sent to a GPCB authorized recyclers. Completion of Drilling On completion of activities, the well will be either plugged and suspended (if the well evaluations indicate commercial quantities of hydrocarbons) or will be killed and permanently abandoned. In the event of a decision to suspend the well, it will be filled with a brine solution containing very small quantities of inhibitors to protect the well. The well will be sealed with cement plugs and some of 21

22 the wellhead equipment (Blind Flange) will be left on the surface (Cellar). If the well is abandoned it will be sealed with a series of cement plugs, all the wellhead equipment will be removed, by leaving the surface clear of any debris and the site will be restored. The Crude oil produces during the well testing at appraisal stage will be collected and sent to nearly and approved waste oil recyclers. Decommissioning & closure of wells After the completion of the drilling activity, partial de-mobilization of the drilling rig and associated infrastructure will be initiated. As discussed earlier, well testing may be carried out immediately after the drilling is completed. The complete de-mobilization of the facilities at site will happen once well-testing completed successfully. This will involve the dismantling of the rig, all associated equipment and the residential camp, and transporting it out of the project area. It is expected that demobilization will take approximately days and will involve the trucking away of materials, equipment and other materials from the site to bring it back to its original condition. It is estimated that about 50 truckloads will be transported out of site during this period. If no indication of any commercially viable amount of oil or gas is encountered either before or after testing, the well will be declared dry and accordingly will be plugged of and abandoned, and the site will be restored in line with regulations and good industry practice. Appraisal When, exploratory drilling is successful, more wells (termed as Appraisal wells) will be drilled to determine the size and the extent of the field. Wells drilled to quantify the hydrocarbon reserves found are called as appraisal wells. The appraisal activity will be carried out with an aim to evaluate the size and nature of the reservoir, to determine the number of confirming or appraisal wells required, and whether any further seismic survey is necessary. The technical procedures and activities in appraisal drilling will be the same as those employed for exploration wells. A number of wells may be drilled from a single well pad/ drill site. Deviated or directional drilling at an angle from a site adjacent to the original discovery well may be used to appraise other parts of the reservoir, in order to reduce the land requirement. Setting up of Early Production Units (EPUs)/ Quick Production Facility (QPF) and Early Production Vedanta Ltd (Cairn Oil & Gas), as an interim plan, in case of commercially viable discovery (s) of hydrocarbons in the block and having established the size of the hydrocarbon field (s), proposes to immediately bring the field (s) into production using one or more of the appraisal wells for the production of crude oil by setting up of Early Production Units (EPUs) or QPUs (Quick Production Units). Early production of the Crude oil will enable the Country to reduce dependence on import of crude oil. Here, it may be noted that after the commercially viable discovery (s) of the hydrocarbon field(s), following the typical life cycle of Oil & Gas Exploration & Production sector, full-fledged field development plan including development well drilling, establishing crude oil & natural gas processing facilities, laying of intra-field & cross country pipelines and other associated physical and social infrastructures will be taken up and prior development EC and other approval will be obtained as applicable. The lead time for entire process is about 3 4 years for the production of crude oil and natural gas. 22

23 Once the full-fledged field development comes up, the Early Production Unit(s)/ Quick Production Unit(s) will suitably be integrated with the full-fledged facilities and/ or phased out. Early Production Units (EPUs) or QPUs (Quick Production Unit) will be installed for the processing of produced well fluid. A EPU/ QPU will be a packaged/ modular mobile unit and will mainly consists of a three phase separator & production heater or heater-treater, oil storage tanks, oil tanker loading system, produced water (PW) separation and disposal system, power generation (GEG or DG), utility systems such as fuel gas, flare & Inst. Air packages, firefighting equipment, etc. Each EPU/ QPU capacity will be ~2,000 BFPD (Barrels of Fluid per Day). The EPUs/ QPUs will be installed near the already established exploration and appraisal well location within the well pad in the commercially viable discovered oil field. The separated crude oil will be stabilized further, stored in storage tanks and subsequently send through road tankers to the nearing available facilities like terminals/ depots. The produced gas will be used for internal heating, power generation purpose as far as possible & surplus gas will be safely disposed off using flare system. The produced water will be treated to achieve MoEF/ CPCB/ SPCB specification (discharge standards) and will be disposed off. The treated effluent (produced water) will be disposed off using either a nearby down hole disposal well (by reinjection in abandoned well) or other available & suitable onshore disposal medium or solar/ mechanical evaporators depending on the feasibility. The power requirement will be met through state electricity grid and/ or installation of Diesel/ Gas Engine Generator(s) using produced gas. The water requirement for the oil and gas processing will be sourced locally through approved authorities or through extraction of ground water. In case of extraction of ground water, permission (NOC) will be obtained from CGWA/ CGWB (Central Ground Water Authority/ Board) of from State Govt. Installation of raw water treatment plant will be done depending on the need for process water and domestic water consumption. The typical broad requirements envisaged for the well fluid processing and production of crude oil and associated natural gas through QPF are the following: Wells with selected artificial lift; & flow lines; Combination of Heater (using produced gas) & 3 phase separator or single heater-treater Stabilized Crude oil storage, pumping & tanker loading facilities; PW separation and disposal system; Fuel gas system, Instrument air/ gas system; Flare system, Firefighting equipment, Raw water treatment plant; Diesel/ Gas Engine Generator (s); Domestic sewage treatment facility (STP or septic tank & soak pit system); 3.6 Raw materials required and source Broad requirements of raw materials: 23

24 Seismic Acquisition The seismic survey will be conducted using dynamite charges. The explosive sources (dynamites) and drilling fluid chemicals for shot hole drilling will be procured by the company before commencement of the operations. During surveying the main tasks include initial installation of a small number of survey control points, then setting-out source points and receiver stations for use. This would be done by the conventional survey method of using RTK GPS backpack surveying units and biodegradable markers. Cutting activities though minimal for the receiver and source lines shall be done manually or mechanically where appropriate. In open areas where there is clear line of sight no cutting shall be done. Recording involves laying of geophones on the receiver stations and generating energy (vibrations) on the perpendicular source lines to generate seismic energy, which are reflected and recorded on magnetic tapes via the recording instrument. Drilling During drilling activities, materials like HSD, Steel (in the form of casings & tubulars) and chemicals like barite, oil well cement and bentonite will be required. Other production equipments like tubular (Casing and tubings), wellhead assembly, packer etc, and chemicals for mud and cementing required for the drilling operations and shall be procured by the company from within the country and from abroad before the commencement of operations. Water based mud will be used for initial, shallower sections where massive shales are not encountered. The deeper and difficult to drill formations will be drilled using synthetic base mud (SBM). Synthetic base mud unlike oil based mud (OBM) is biodegradable but can be re-used. WBM typically consists of water, bentonite, polymers and barite. Other chemical additives viz. glycols and salts may be used in conjunction to mitigate potential problems related to hydrate formation. Requirement WBM (approx.) m 3 /well Requirement SBM (approx.) m 3 /well 3.7 Resource optimization/ recycling and reuse envisaged in the project Maximum care will be taken for resource optimization, wherever possible with an aim of Resource Conservation Elimination of Waste Streams Minimizing Waste Reuse / Recycle of Wastes The drill cuttings from the drilling operations associated with water based mud will be used for filling low lying areas as a sub grade construction material in construction of well pads etc. Synthetic base mud will be re-used in further drilling activities. 3.8 Water and power requirement Water Requirement Seismic Operations: The water required during seismic operation will be mostly for domestic use which is about m3/day. 24

25 Drilling Operations: Drilling Operations: The water requirement in drilling rig is mainly meant for preparation of drilling mud apart from washings and domestic use. While former constitutes majority of water requirement, latter or the water requirement for domestic and wash use is minor. Water for both process and domestic uses would be procured through surface water sources. The water requirement per well is shown in below in Table 4. Table 4: Water requirement Description Water for domestic use Quantity m 3 /well/day Drilling water consumption for mud preparation m 3 /well (WBM) and m 3 /well (SBM) Water requirement for miscellaneous use (Engine cooling, floor/equipment/string wasteline, firefighting, storage/makeup) during drilling phase (KL) m 3 /well/day The water requirement for all the project activities will be sourced locally through approved/ authorized sources of surface water and/ or ground water (e.g. PHD bore wells, privately owned bore wells, Irrigation Dept./ Water Resources Dept. of State Govt.). In case, required water could not be sourced from locally available approved sources, ground water will be extracted after obtaining permission from CGWA/ State Govt Power Requirement During Seismic Operations The power requirement during seismic is 350 KVA will be provided through diesel generator (DG) sets or state electricity grid. During Drilling Operations The power requirement in the drilling site and the campsites will be provided through diesel generator (DG) sets. The rated capacity of the DG sets required for onshore drilling site is provided in following table. Details of DG sets of Onshore Drilling Activity Location Camp site Drilling site Radio Room DG Capacity 2 X 350 kva (one working and one standby) 3 x 1000 kva ( two working and one standby) 2X100 kva 3.9 Quantity of waste to be generated and its disposal During Seismic Operation: Insignificant amount of waste water will be generated from domestic use and the same shall be disposed through septic tanks/soak pits. The Air emissions and noise emissions will be also very insignificant and will be temporary in nature. Domestic effluent of about m 3 /day is anticipated. Also, non-hazardous solid wastes like food waste, paper, etc. are expected. 25

26 During Drilling Operations: Waste water generation The drilling operation would generate wastewater in the form of wash water due to washing of equipment, string and cuttings etc. The only other source of wastewater generated from drilling operation is sewage from sanitation facilities, around m 3 /day/well, which shall be disposed through septic tanks/soak pits. It is expected that wastewater in the form of Drill cutting washing + Rig washing+ cooling etc shall be generated at an average rate of around m 3 /day/well during the drilling operations from a single well. Waste water will be discharged in HDPE lined evaporation pit for disposal, size of the pit is generally 50mx20mx1.5m. The wash water would contain variable quantities of mineral salts, solids, suspended and dissolved hydrocarbons, and other organic and inorganic components in very minor quantities. Waste Management The drill cuttings and spent drilling mud will be generated at site per well during drilling operations. This will be stored in well-designed HDPE line pit. It will be tested for its hazardous constituents (Oil and Grease), If found to be hazardous, It will be handed over to authorized TSDF. In case of Nonhazardous, it will be disposed insitu in HDPE lined pit. Used /waste Oil During the drilling approx. 1-2 tons/well of spent oil will be generated per well. This oil will be sent to authorized recyclers. Domestic waste of kg/day per well will be generated at site, which will be segregated at source (Organic / Inorganic) and disposed accordingly. Disposal of wastes will be as per prior approval of CPCB /SPCB. The expected waste generation from well drilling will be as per Table 5. S.N Nature of waste Quantity during Drilling Activities A Hazardous Waste 1 Drill cuttings associated with WBM Drill cuttings associated with SBM tons/well m3 per well tons/well 2 Spent /Residual drilling mud tons/well 3 Used Lubricating oil, Sludge containing oil and other drilling work B Non Hazardous Waste 1-2 tons/well tons/well 4 Food waste Kg per well 5 Non-combustible waste containing metallic residues, glass 6 Packaging wastes including drums, wooden pallets, plastic containers, plastic foils. 7 Left over chemicals and materials, scrap metal, sludges, scales, batteries, spent acids, spent lubricants, filters etc Kg/well 1000 kg/well kg/well 8 Cement, grit, blasting and painting wastes. 500 kg per well 3.10 Schematic of Feasibility Drawing The typical layout of a well pad/drill site for exploratory and appraisal well is as below: 26

27 Figure9: Schematic for a typical Well Pad Each exploratory & appraisal well drill site will require the following: Potable office cabins / rest rooms (container type cubicles); Drilling rig foundation and cellar; Foundation / Pits for equipment; Space for drill rig equipment, working area and materials lay down area; Waste storage pits; Cutting disposal (impervious lined) pits; Solar evaporation pits (waste drilling fluid disposal); Water storage pit; Septic tank with soak pits; Paved and contained chemical storage area; Above ground Diesel storage tanks with paved and bunded area; Below ground level flare pit (well testing); Provisional space for definitive fracking program. Radio room; Storm water drainage system; Internal roads and fencing. The drill site is restricted access area and is fenced all round with round the clock watch. Entry of vehicles into the drilling site area is prohibited except for material movement. Adequate parking are provided outside the drilling location. 4. Site Analysis 4.1 Connectivity 27